(CNN) -- Eight Florida teenagers -- six of them girls -- will be tried as adults and could be sentenced to life in prison for their alleged roles in the videotaped beating of another teen, the state attorney's office said Thursday.

The teenagers seen in a video assaulting a 16-year-old could face life in prison.

The suspects, who range in age from 14 to 18, all face charges of kidnapping, which is a first-degree felony, and battery, said Chip Thullbery, a spokesman for the Polk County state attorney. Three of them are also charged with tampering with a witness.

Everyone involved in the case was under a gag order imposed by a judge. The only attorney for the teens who has been publicly identified did not return calls from CNN, and his assistant cited the gag order as the reason. The teens are scheduled for their first appearance in court Friday.

The video shows a brutal scene: The 16-year-old victim is punched, kneed and slapped by other girls. She huddles in the fetal position, or stands and screams at her attackers, but the assault continues. Authorities say the eight teens said they were retaliating for insults posted on the Internet by the attack victim.

Polk County Sheriff Grady Judd called the March 30 attack "animalistic."

"I've been involved in law enforcement for 35 years, and I've seen a lot of extremely violent events, but I've never seen children, 14 to 18 years of age, engage in this conduct for a 30-minute period of time and then make these video clips," he said. Police say the teens planned to post the video on YouTube. Watch the disturbing video »

The victim, a 16-year-old from Lakeland, Florida, was hospitalized, and still has blurred vision, hearing loss, and a swollen face, her mother told CNN on Wednesday.

The video shows only girls doing the beating; Judd said the boys acted as lookouts.

The idea of girls administering a vicious beating so they can post the video online may seem shocking, but it's becoming an increasingly common scenario, according to experts and news reports. Watch why more teens are putting fights online »

A search for "girl fight" on YouTube gets thousands of results, and a suggestion to also try "girl fight at school, boy girl fight" and other search terms. There's at least one Web site devoted exclusively to videos of girls fighting.

In 2003, 25 percent of high school girls said they had been in a physical fight in the past year, according to a survey by the Centers for Disease Control and Prevention. (The figure for boys was 40.5 percent.)

A Justice Department report released in 2006 showed that by age 17, 21 percent of girls said they had assaulted someone with the intent to cause serious harm.

Frank Green is executive director of Keys to Safer Schools, a group that studies and tries to prevent school violence. He said he's not sure whether girls have actually become more violent, or whether there's just more awareness of their fights.

"In one respect, girls have always been more vicious than boys," Green said. "Their violence is of a personal nature." He said boys usually have some focus and a concrete goal when they fight. "But girls want to cause pain and make the other girl feel bad," he said.

Judd, the Polk County sheriff, said an important part of the plan in the Lakeland attack was to post the video of the beating on YouTube to humiliate and embarrass the victim.

"It's the next stage of cyberbullying," psychologist Susan Lipkins said. "They want to show what they're doing."

"Our kids are being peer pressured, in another sense of a trend, to put these shock videos out there at other peoples' expense," said Talisa Lindsay, the victim's mother. "And I hope that it doesn't come to the point where there's more people's lives that are being affected by having to take a beating for entertainment, or possibly being killed." Watch mother describe how the victim is doing »

The suspects didn't have a chance to post the video online before police moved in and seized it, Judd said. The Sheriff's Department made it public, and it wound up on YouTube anyway. Judd recognizes the irony.

"In a perverted sense, we were feeding into exactly what the kids wanted," he said. "But according to Florida law, [the video] is public record, and it's going to be in the public domain whether we agree with that or not."

Judd said the suspects showed no remorse when they were arrested and booked.

"They were laughing and joking about, 'I guess we won't get to go to the beach during spring break.' And one ... asked whether she could go to cheerleading practice," he said.

Lipkins, the psychologist, says there's a "disconnect between their actions and their thoughts."

"They think the entire society is doing it, and they think it's funny. So they put it on YouTube. And I don't think they expect kids to get really hurt, and they also don't expect to get really caught."E-mail to a friend